1. Field of the Invention
This invention relates to a method and an apparatus for forming images on an image bearing member on both surfaces of a sheet.
2. Related Background Art
A film as shown in FIG. 5 of the accompanying drawings has heretofore been available as a film used with an apparatus such as a microfilm reader-printer. On this film 4, image frames 3 are recorded in two rows and retrieval marks m are provided on one side edge of the image frames 3. The photographing system for such film 4 is called duplex, which involves a method whereby the images on the front surface of an original are photographed on one side edge portion of the film 4 in succession from the leading end thereof and at the same time the images on the back surface of the original are photographed on the remaining side edge portion of the film. In the example shown, for convenience, the image frames 3 are given numbers in succession from the leading end of the film.
To copy the images of the image frames 3 of the film 4, the image frames 3 on one side edge portion of the film 4 have been successively copied on one surface of copying paper, whereafter the film has been rewound to the leading image frame 3, and then the image frames on the remaining side edge portion have likewise been successively copied on one surface of copying paper.
In the case of such prior art, however, even if a plurality of rows of image frames 3 are photographed on the film 4, all the image frames 3 of the film 4 are copied only one surface of a sheet of copying paper and therefore, the same number of sheets of copying paper as the number of images to be copied is required, and for an information recording medium such as microfilm which is capable of recording a great deal of originals thereon, the consumption of copying paper becomes enormous. Further, and there has also been the problem that associated image frames 3 are copied on different sheets of copying paper and the handling of the copying paper is cumbersome.